I've successfully decrypted one hash using JTR, but for some reason every other attempt I've made has failed.

My password file at the moment has only the one line:

user:3f39588bb19e28051d9aedfbb170025c

The hash is md5. I run it, and it says that there are 2 hashes with no salts, and then can't crack it. There are no spaces before, after or in the line, and I just can't understand why it thinks there are two hashes rather than one.